| TP Personal Development Limited | Arts & recreation | 2025 |
| TPS (Luton) Ltd | Households | 2015 |
| TQ14 Properties Ltd | Real estate | 2024 |
| Traac Ltd | Construction | 2024 |
| Trabzon Catering Ltd | Hospitality | 2023 |
| Tractist Ltd | Information & communication | 2023 |
| Tracy ANN Arkhurst Consultancy Ltd | Information & communication | 2017 |
| Tracy Hill, Jigsaw Safety Ltd. | Professional & scientific | 2015 |
| Tracy ROE Hairdressing Limited | Other services | 2000 |
| Trade Accord (UK) Ltd | Extraterritorial | 2008 |
| Trade Central Ltd | Health & social care | 2025 |
| Trade for Real Ltd | Professional & scientific | 2023 |
| Trade GH Ltd | Real estate | 2024 |
| Trade Hub Luton Ltd | Administrative & support | 2023 |
| Trade Large Ltd | Transport & logistics | 2018 |
| Tradeflow Management Services Ltd | Wholesale & retail | 2025 |
| Tradeship Ltd | Wholesale & retail | 2025 |
| Tradesmen Dispute Direct Ltd | Professional & scientific | 2026 |
| Tradiemate Ltd | Information & communication | 2026 |
| Traditional Coving UK Ltd | Manufacturing | 2021 |
| Tradyon Academy Ltd | Information & communication | 2025 |
| Tradyon Goods Ltd | Wholesale & retail | 2025 |
| Trail Studio Ltd | Professional & scientific | 2020 |
| TRAIN2EDUCATE Ltd | Education | 2025 |
| Training 4 U Services (UK) Ltd | Education | 2009 |
| Training Academy Enterprises Limited | Education | 2013 |
| Training Code Ltd | Education | 2020 |
| Tralej Ltd | Health & social care | 2020 |
| Trampon Ltd | Construction | 2024 |
| Trandafir Brothers Ltd | Transport & logistics | 2026 |
| Trandafir Transport Ltd | Transport & logistics | 2019 |
| Trans Arabia Contracting Limited | Information & communication | 2026 |
| Trans Express Eppur SI Muove Ltd | Transport & logistics | 2026 |
| Trans MC Limited | Construction | 2019 |
| Transacta General Training Fz-Llc Limited | Information & communication | 2025 |
| Transcend Healthcare Ltd | Real estate | 2022 |
| Transcendent DRC Solutions Ltd | Information & communication | 2024 |
| Transe Academy Limited | Education | 2011 |
| Transe Ltd | Information & communication | 2007 |
| Transeform Property Ltd | Real estate | 2020 |
| Transform Decorators & Cleaning Services Ltd | Construction | 2020 |
| Transform Training Consultancy Ltd | Administrative & support | 2015 |
| Transilvania Centre Ltd | Wholesale & retail | 2023 |
| Transit Deal Ltd | Transport & logistics | 2026 |
| TRANSKAROL2 Limited | Transport & logistics | 2024 |
| Transkart UK Ltd | Transport & logistics | 2025 |
| Translg Limited | Transport & logistics | 2023 |
| Transpepe Ltd | Transport & logistics | 2017 |
| Transpire Consulting Limited | Information & communication | 2025 |
| Transport Direct Solutions Ltd | Transport & logistics | 2024 |
| Transport Mili Limited | Transport & logistics | 2022 |
| Transport Parllaku Ltd | Transport & logistics | 2021 |
| Transport Service Limited | Transport & logistics | 2026 |
| Transporter Number One Services Ltd | Transport & logistics | 2023 |
| Transportly Ltd | Wholesale & retail | 2022 |
| Trasner Ltd | Professional & scientific | 2023 |
| Travel Choice Limited | Extraterritorial | 2004 |
| Travel PAD Limited | Information & communication | 2025 |
| Travelstone Ltd | Transport & logistics | 2018 |
| Travis Driveways Ltd | Administrative & support | 2018 |
| TRB Couriers Ltd | Transport & logistics | 2023 |
| TRD Transport Ltd | Transport & logistics | 2026 |
| Treadwin Automotive Group Ltd | Manufacturing | 2023 |
| Treasures Home Limited | Health & social care | 2023 |
| Treats Luton Ltd | Wholesale & retail | 2023 |
| Treatz Luton Ltd | Hospitality | 2015 |
| Treble a Holdings Ltd | Real estate | 2026 |
| Treecutter Ltd | Administrative & support | 2024 |
| Treetop Nursery Limited | Education | 2010 |
| Trelanoak Limited | Financial services | 1990 |
| Treleaven Financial Services Limited | Administrative & support | 2018 |
| Trelix Property Management Limited | Households | 2026 |
| Trend Accessories Limited | Wholesale & retail | 2025 |
| Trend Investment Group Ltd | Real estate | 2022 |
| Trendaset Limited | Wholesale & retail | 1986 |
| Trendexia Ltd | Wholesale & retail | 2025 |
| Trendivibe Ltd | Wholesale & retail | 2025 |
| Trends&Troves Ltd | Wholesale & retail | 2026 |
| Trendz Hair Design Luton Ltd | Administrative & support | 2017 |
| Trendz Hub Ltd | Wholesale & retail | 2025 |
| Treney Limited | Other services | 2022 |
| Trenzora Ltd | Wholesale & retail | 2025 |
| Tressence UK Ltd | Wholesale & retail | 2025 |
| Trevor Minott Ltd | Professional & scientific | 2025 |
| Treyvon Ltd | Health & social care | 2013 |
| Tri-Ag Design Ltd | Wholesale & retail | 2018 |
| Trialliance Trade Ltd | Wholesale & retail | 2026 |
| Trident and Haulage Limited | Transport & logistics | 2025 |
| Trifan Transport Services Ltd | Transport & logistics | 2022 |
| Trifly Automotive Ltd | Wholesale & retail | 2026 |
| Triggering Trends Ltd | Wholesale & retail | 2023 |
| Tril Design & Developments Ltd | Construction | 2020 |
| Tril Homes Limited | Real estate | 2025 |
| Trilite Limited | Manufacturing | 2012 |
| Triman Developments UK Limited | Construction | 2005 |
| Trinethra Limited | Hospitality | 2025 |
| Trinity Close (Luton) Management Ltd | Households | 2013 |
| Trinity Family Time Limited | Health & social care | 2025 |
| Trinity Property Ltd | Real estate | 2017 |
| Trinity Solar Limited | Professional & scientific | 2005 |